Broken valve spring. What else might be damaged?

[ecallaway]

From what I can gather from the forums, valve springs get old and break. And then they can be replaced. But I am concerned that there might be other damage, so just replacing the broken spring could result in bigger problems. Should I just have a complete rebuild done?

This is a 1955 beetle with the original engine. After the spring broke I ran the engine on 2 cylinders for about 15-20 minutes total over a 2-3 week period while trying to diagnose and fix problems. When I finally got to removing the valve cover I found a bunch of oil in there and the valve retainer and keepers were loose inside. The #1 intake valve is jammed under the rocker. When I advance the engine manually, all the other rockers seem to move properly and the push rod for #1 intake moves as it should. Can I just get a new spring, retainer, and keepers and put it all back together without removing the engine? Well I could ... but should I?

[esde]

Does the valve move all the way open and closed -without binding? If you hold it closed, and then spin it, does it turn smoothly? If it chatters as it goes around, or binds while opening it's probably hit the piston and bent. Then the head needs to come off. If it feels good, replace all the springs. I feed a few feet of clothesline into the cylinder through the spark plug hole, then turn it to top dead center. (Leave the end of the clothesline hanging out!) This forces the ball of line up against the valves and holds them closed while you replace the springs. Works much better than the compressed air method, which usually leaks on old worn engines.
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[VW_Jimbo]

Why not? You got nothing to lose. Right? If it breaks a spring again, you have to rebuild the motor. If the valve break in half, you have to rebuild the motor. Anyway you roll the dice on this, you are rebuilding the engine if it does not work out. So, go for it! I have replaced a few broken springs through the years with no I’ll effect on the engine. The last few have been in conjunction of having rusty springs! Go figure! That rust acts as a weak spot in the spring for some reason. Makes sense though.
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[ecallaway]

[ecallaway]

[ecallaway]

[VW_Jimbo]

[ecallaway]

[ecallaway]

[splitjunkie]

[VWFIXER]

I replaced a spring on an intact engine along side of the road in Kapaa for a friend. Big Diesel dump truck. With OEMTOOLS 27040 Valve Spring Compressor, $25
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Over a million air cooled miles driven and 15,000+ cars serviced.

[VW_Jimbo]

[ecallaway]

Thanks all. It's good to hear different perspectives on this. Another factor to weigh in is that I was already thinking of a rebuild because compression was on the low side when I took possession of the car 2 years ago.

[esde]

Here's my take on it:
If it was a 1600, sure take a gamble. The heads are everywhere and available new.
But 36hp heads have not been reproduced, and only 1 in 3 (my experience) is even able to be rebuilt, so I personally wouldn't take a chance unless I was sure the valve was straight.
I don't know if the spring tool for a 1600 will work o. the 36, but if it will changing the springs on the entire engine is no big deal
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modok wrote:
Bent cranks are silent but gather no moss. I mean, ah, something like that.

[ecallaway]

Well .... off with the head.

Took off the rocker arm and the valve stem is bent at its thinnest point. It will not turn easily in the guide or slide in and out easily. You can see in the picture that the valve stem does not align properly with the rocker arm. The spring is broken in 2 places so probably when it broke there was enough slack for the retainer and keepers to come off and then the force of the rocker arm bent the valve stem. Hopefully there was not also a collision with the piston. The rocker arm seems fine.

So the engine will come out, the head will need to come off and we will see what it looks like from the inside. Most likely I will just take the engine out and bring it to a good rebuilder.

[raydog]

[ecallaway]

Just now realizing that I should link my posts about valves and pistons/cylinders since they are related.

https://www.thesamba.com/vw/forum/viewtopic.php?t=...highlight=

After removing the heads it was not much of a stretch to also take off the cylinders and pistons. Turns out that nothing from the valve spring breaking did any damage to the pistons or cylinders. So if the pistons and cylinders had been new and in good condition it would have been fine to rework the heads and replace the springs and valves. But the pistons were worn so I am replacing all the pistons and cylinders.

[sunroof]

Measure the end play. If it is out of spec then the whole thing should come apart. However! 36ers are very tough and will last a long time if treated with care while driving. It looks like #1 spring broke. Let us know how #3 and 4 look as well. #3 can easily kill you motor. As for useable 36 heads... I have 4 and all of them are cracked so yeah, save them if you can. Good luck!

Don
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[ecallaway]

Yes, everything came apart and heads were machined. All new valves and springs. New pushrods and tubes. New pistons and sleeves. Getting all my tin blasted and powdered and new tar board before putting everything back together.

[sunroof]

Pictures please!

Remember it's not porn if there are no images.

Don
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Better and better mistakes!